Seismic assessment and upgrading of existing non-conforming multi-storey steel buildings: A case study

While dealing with existing steel constructions, an high level of variability is encountered with reference to structural conception and typology of load-carrying systems. Furthermore, such structures often prove to be non-compliant with current codes, thus showing crucial structural shortages in many cases. Within this framework, an existing non-conforming six-storey steel building is in this article as a case study. The selected construction features both Moment Resisting Frames (MRFs) and Concentrically Braced Frames (CBFs) along its two main directions in plan. The seismic response of the selected structure was assessed in compliance with Italian and European standards, resulting in an inadequate performance and insufficient capacity. Hence, a global seismic refurbishment was conceived and numerically checked. Finally, results for the upgraded structure are compared to the performance of the as-built configuration.